性、味、畏、忌俱同生地黄。用砂锅、柳甑，衬以荷叶，将生地黄酒润，用缩砂仁粗末
拌蒸
，盖复极密。文武火蒸半日，取起，贮极干。如前又蒸九次，为度。令中心透熟，纯黑乃佳
。
滋肾水，封填骨髓。利血脉，补益真阴。久病余，胫股酸痛。新产后，脐腹急疼。
地黄合地之坚凝，得土之正色，为补肾要药，益阴上品。禀仲冬之气，故凉血有功，阴
血赖
养。新者生则瘀者去，血受补则筋受荣，肾得之而骨强力壮矣。胎产劳伤，皆血之愆，血得
其养，证因以痊，肾开窍于二阴，况血主濡之，二便所以利也。湿热盛则食不消，地黄去湿
热以安脾胃，宿滞乃化，掌中应心主，痿蹶乃脾热，奉君主而清其仓廪，两证可瘳矣。熟者
稍温，补阴补血，滋肾养肝，其功更溥。六味丸以之为首，天一所生之本也。四物汤以之为
主，乙癸同源之义也。久病阴伤，新产血败，在所极需。
生地黄，性寒而润，胃虚食少，脾虚泻多，均在禁例。熟者性滞，若痰多气郁之
人，能窒碍胸膈，当斟酌用之。姜酒拌炒，生者不妨胃，熟者不泥膈。
味甘，性平，无毒。入脾经。
益气养阴，补脾润肺。肺燥干咳，气馁消渴。体虚乏力，用以服食。
味甘气和，为益脾阴之剂，土旺则湿除，故又能祛湿。
[Background Information]
Book: Bencao Zhengyao (Essentials of Materia Medica)
Author: Li Zhongzi
Dynasty: Ming
Chapter: (III) Nourishing Yin / (III) Nourishing Yin
Category: Materia Medica
[Original Text Processing]
The nature, flavor, aversions, and contraindications are all the same as Sheng Di Huang (Rehmanniae Radix). Use a clay pot and a willow steamer, line with lotus leaves, moisten Sheng Di Huang (Rehmanniae Radix) with rice wine, mix with coarse powder of Sha Ren (Amomi Fructus), and steam. Cover tightly. Steam over moderate heat for half a day, remove, and store until extremely dry. Repeat the steaming process nine more times as above to complete the preparation. Ensure the center is thoroughly cooked; pure black color is ideal.
It nourishes Kidney Water (Kidney Yin), seals and fills the bone marrow. It benefits the blood vessels and tonifies True Yin (True Essence). For residual symptoms after prolonged illness, such as soreness and pain in the shins and thighs. For urgent abdominal pain after recent childbirth.
Di Huang (Rehmannia Root) combines the firmness and solidity of Earth, obtains the correct color of Earth, and serves as an essential herb for tonifying the Kidney and a superior product for benefiting Yin. Endowed with the Qi of mid-winter, it has merit in cooling Blood and nourishing Yin-Blood. When fresh, it generates; when used, stasis is removed. When Blood is tonified, tendons receive nourishment. When the Kidney receives it, bones become strong and muscles powerful. Trauma from pregnancy, childbirth, or overwork are all errors related to Blood. When Blood receives its nourishment, the conditions recover. The Kidney opens into the two lower orifices. Moreover, since Blood primarily moistens them, urination and defecation thus become smooth. When Damp-Heat is excessive, food is not digested. Di Huang removes Damp-Heat to calm the Spleen and Stomach, so that retained stagnation transforms. The palm corresponds to the Heart Master. Wei Jue (Flaccidity and Cramping) is due to Spleen Heat. Serving the Monarch (Heart), it clears its granaries, and these two conditions can be cured. Cooked Di Huang is slightly warm; it tonifies Yin and Blood, nourishes the Kidney and Liver, and its efficacy is even more extensive. Liu Wei Wan (Six-Ingredient Pill with Rehmannia) uses it as the primary ingredient, representing the root of "One Heaven Generates." Si Wu Tang (Four Substance Decoction) uses it as the main component, embodying the principle that "Yi [Liver/Wood] and Gui [Kidney/Water] share the same source." It is extremely needed for Yin injury from prolonged illness and Blood destruction from recent childbirth.
Sheng Di Huang (Rehmanniae Radix) is cold in nature and moistening. Cases of deficient Stomach with poor appetite and deficient Spleen with frequent diarrhea are both contraindications. Cooked Di Huang has a cloying nature; for persons with much phlegm and Qi stagnation, it may obstruct the chest and diaphragm, so use with discretion. Stir-frying with ginger and rice wine ensures that raw Di Huang does not harm the Stomach and cooked Di Huang does not stick to the diaphragm.
Sweet in flavor, neutral in nature, non-toxic. Enters the Spleen Meridian.
Benefits Qi and nourishes Yin, tonifies the Spleen and moistens the Lungs. For dry cough due to Lung Dryness, depleted Qi, and Xiao Ke (Wasting-Thirst). For physical weakness and fatigue, used for dietary therapy.
Its flavor is sweet and its Qi is harmonious, making it a formula that benefits Spleen Yin. When Earth is prosperous, Dampness is eliminated, so it can also dispel Dampness.